1. Field of the Invention
The present invention relates to a tactile screen for determining the coordinates of a point on a surface, a screen support being provided with relatively spaced conductive strips made up of emitting strips and receiving strips in interjacent relation. Said screen is intended to be touched by an object such as a user's finger in order to establish an electrical bridge between an emitting strip and a receiving strip. The variation in electric potential on each emitting strip and receiving strip is measured in order to deduce therefrom the coordinates of the point of contact of the object aforesaid on the screen.
2. Description of the Prior Art
A tactile screen of this type has been described in French Pat. No. 2,520,498 granted to the present Applicant.
The present Applicant has observed that the operation of the device considered in the foregoing was sometimes liable to be disturbed when placed in a moist or dirty environment.
Moreover, the operation of this device is influenced by the variations in electrical resistance of the operator's finger or of the object employed for establishing an electrical bridge between the conductive strips of the screen.
The aim of the present invention is therefore to optimize the operation of the known tactile screen discussed above, irrespective of the physiological conditions of the operator or the conditions of the external medium in which the screen is located.